Randy E. Barnett justifies natural rights conditionally, basing them on our appreciation of certain social goods. He emphasizes that "if we want a society in which persons can survive and pursue happiness, peace and prosperity, then we should respect the liberal conception of justice—as defined by natural rights—and the rule of law." Not everyone values freedom, harmony, and wealth, of course. Most of us do, though, and together we easily number enough to enjoy the comforts and pleasures of human society.

We live together amicably because we recognize and respect certain natural rights. Which ones? Barnett names private property—including our property rights in our bodies—and freedom of contract. Since property protects both the right to it and the right against trespass, it corresponds to common law's property and tort rules. Freedom of contract, which includes the right to contract and to not contract, corresponds to common law's contract rules. Barnett's description of natural rights thus matches the protections of persons, property, and promises at the heart of common law.

Barnett expressly includes "physical resources" in his description of property rights. "Such property rights are 'natural' insofar as, given the nature of human begins and the world in which they live, they are essential for persons living in society with others to pursue happiness, peace, and prosperity." Do copyright rights qualify as natural on that description? Probably not.

Barnett offers a positivist account of natural rights, an approach earlier developed by F.A. Hayek. Social values evolve and develop to enable human flourishing, Hayek explained. "[G]roups which happen to have adopted rules conducive to a more effective order of actions will tend to prevail over other groups with a less effective order," he said. That hardly means that groups with especially efficient rules conquer and crush their less developed neighbors. "It is more likely that the success of the group will attract members of others which then become incorporated in the first."

That competition between social orders spontaneously generated natural rights long before states arose. "Long before man had developed language to the point where it enabled him to issue general commands, and individual would be accepted as a member of a group only so long as he conformed to its rules," Hayek explained. David Hume expressed the same point with characteristic grace:

But tho' it be possible for men to maintain a small uncultivated society without government, `tis impossible they shou'd maintain a society of any kind without justice, and the observance of those three fundamental laws concerning the stability of possession, its translation by consent, and the performance of promises. These are, therefore, antecedent to government, and are suppos'd to impose an obligation before the duty of allegiance to civil magistrates has once been thought of.

Our rights to persons, property, and promises qualify as "natural" because they have evolved to enable human social life. They long predate the State. Copyright, in contrast, arose only relatively recently, in complete reliance on a non-customary, exceptional, statutory privilege.

[NB: The above text comes from chapter 2, § C.2 of my draft book, Intellectual Privilege: Copyright, Common Law, and the Common Good. You can find a PDF of the entire chapter, including footnotes, here. I welcome your comments.]